The present invention relates to a video special effect generator for producing a video special effect on an input image and, more particularly to a video special effect generator for producing a video special effect on an input image by use of a contour signal which detects a contour of the input image.
Video special effect generators heretofore detect a contour of an input image and generates a wide variety of video special effects such as emphasis and blur on the detected contour. Japanese patent applications Nos. 63-225323 and 01-52150 or corresponding U.S. patent application Ser. No. 5,101,440 describes a video special effect generator wherein a contour of an input image is detected, a detected contour is converted into a flat histogram and an input image is converted into a line picture by synthesizing the converted contour to the original input image.
However, there has not hitherto been proposed a video special effect generator which can generate a video special effect on the video signal such that a contour of an input image is detected and not only the contour but also the original input image itself are converted by use of a contour signal indicative of a detected contour. In particular, there has not hitherto been proposed a video special effect generator which can generate a video special effect on a video signal such that only a contour of an image of a past frame is superimposed upon an input image of the present frame as a residual image by use of contour information.